Spin-on filter for a filter device for fluid, filter device and filter head of a filter device

ABSTRACT

A spin-on filter for a filter device with a housing pot in which a filter element is arranged, a connecting body arranged at the housing port end face having a central opening and a fluid opening radially outwardly offset from central opening. A filter-side coupling part of a coupling device detachably couples the spin-on filter to a filter head. The coupling part can be detachably coupled to a connector of a head-side coupling part of the filter head by way of a plug-in and/or rotational movement with respect to a coupling axis. A inner seal is provided having a sealing surface which extends around the periphery of a centric fluid channel and is axially offset in relation to the filter-side coupling part toward the filter element. The circumferential sealing surface of the filter head-side fluid connector sealingly contacts to separate the dirty and clean sides.

TECHNICAL FIELD

The invention relates to a spin-on filter for a filter device for fluid,in particular liquid, in particular oil or fuel, in particular of aninternal combustion engine, in particular of a motor vehicle.

The invention further relates to a filter device for fluid, inparticular liquid, in particular oil or fuel, in particular of aninternal combustion engine, in particular of a motor vehicle. Theinvention moreover relates to a filter heat of a filter device forfluid, in particular liquid, in particular oil or fuel, in particular ofan internal combustion engine, in particular of a motor vehicle.

BACKGROUND OF THE INVENTION

A filter device including a filter head and a filter cartridge is knownfrom EP 0 830 885 A1. The filter cartridge is secured to the filterhead. The filter head includes a plurality of outwardly extending rampedprojections constituting a first component of a bayonet-type coupling.The ramped projections are cooperable with similar projections of thefilter cartridge to secure the filter cartridge to the filter head.

SUMMARY OF THE INVENTION

It is the object of the invention to devise a spin-on filter, a filterdevice, and a filter head of the type mentioned above, in which aseparation of a dirty side of the easy-change filter, in particular ofthe spin-on filter, from a clean side in the region of the couplingdevice can be improved.

This object is achieved according to the invention by the spin-on filterincluding:

-   -   a housing pot, in which a filter element is arranged;    -   a connecting body, which is arranged at the end face of the        housing pot and is provided with a central opening, and in        particular with at least one fluid opening that is radially        outwardly offset in relation to the central opening;    -   a filter-side coupling part of a coupling device for detachably        coupling the spin-on filter to a filter head of the filter        device, the coupling part being arranged on the central opening,        wherein the filter-side coupling part can be detachably coupled        to a connector of a head-side coupling part of the filter head        by way of a plug-in and/or rotational movement with respect to a        coupling axis, and wherein an inner seal is provided, having a        sealing surface which extends around the periphery of a centric        fluid channel and is axially offset in relation to the        filter-side coupling part toward the filter element, and against        which a circumferential sealing surface of a filter head-side        fluid connector can be sealingly placed so as to separate a        dirty side from a clean side of the spin-on filter.

Such spin-on filters are also known to be referred to as easy-changefilters or screw-on filters. At least one filter element is arranged inthe housing pot of the filter housing in the case of the spin-on-filter.The spin-on filter is replaced entirely together with the filter housingand the at least one filter element contained therein. Advantageously,the at least one filter element may be fixedly arranged in the filterhousing.

The fluid channel can advantageously be a fluid outflow channel throughwhich the fluid can exit the interior of the filter element. If the flowthrough the filter element is reversed, the fluid channel can also be aninflow channel through which fluid can reach an interior of the filterelement.

The fluid connector can advantageously be a fluid outflow connector viawhich the fluid can flow out of the spin-on filter. Alternatively, thefluid connector can also be an inflow connector via which the fluid fromthe filter head can reach the spin-on filter. The fluid connector canadvantageously be a section of a connection piece, in particular of aconnecting sleeve section, of the filter head.

The spin-on filter or the filter device is in particular designed suchthat unfiltered fluid is fed on one end face, and the filtered fluid isdischarged on the same end face.

Against this background, at least one eccentric fluid opening of theconnecting body can advantageously be a fluid inflow opening throughwhich fluid can reach the spin-on filter. As an alternative, the atleast one fluid opening can be a fluid outflow opening through whichfluid can exit the spin-on filter.

Alternatively, however, it is also possible for both the untreated fluidand the treated fluid to flow via the central opening into the filter orout of the filter.

The connecting body can advantageously be a connecting plate. Theconnecting body can advantageously be a cover of a housing of thespin-on filter. The cover can advantageously be used to cover thehousing pot.

The head-side coupling part can advantageously be designed as aconnector. The head-side coupling part can alternatively also comprise asection that has the function and/or shape of a connector.

The inner seal can advantageously be arranged offset axially withrespect to the coupling axis in relation to the filter-side couplingpart toward the interior of the spin-on filter.

In an advantageous embodiment, the sealing surface of the inner seal canform an at least axial, with respect to the coupling axis, contact forthe sealing surface of the head-side fluid connector.

In a further advantageous embodiment, the inner seal can be coupled tothe filter element.

In a further advantageous embodiment, the filter-side coupling part cancomprise multiple coupling ribs, which are distributed in thecircumferential direction of the coupling axis on the central opening.

The connecting ribs can advantageously be continuous circumferentiallywith respect to the coupling axis. The coupling ribs can also includeinterruptions circumferentially with respect to the coupling axis.

The coupling ribs, on the side thereof facing away from the filter head,can include at least one respective filter-side retaining surfaceextending obliquely with respect to the coupling axis, and on the sidethereof facing the filter head, they can include at least one respectivefeed ramp extending obliquely with respect to the coupling axis, whichcan be used to feed head-side retaining surfaces on the head-sidecoupling part to the filter-side retaining surfaces when the spin-onfilter is being mounted to the filter head, while rotating the spin-onfilter.

The coupling ribs can advantageously be arranged on a radially innercircumferential side of the connecting body.

The coupling ribs can advantageously project radially inwardly. Thecoupling ribs can advantageously project radially inwardly into thecentral opening.

In this way, a stable and compact shape can be implemented. The couplingribs can be arranged on an inner circumference of the central opening.

Starting sections of the coupling ribs facing the filter head mayadvantageously be distributed, in particular uniformly distributed,circumferentially with respect to the coupling axis.

In this way, the risk of the spin-on filter tilting during attachment tothe filter head can be reduced, and preferably prevented.

Starting sections of the coupling ribs facing the filter head mayadvantageously be spaced axially, with respect to the coupling axis,from a head-side radially inner edge of the connecting body surroundingthe central opening.

In this way, a section of the radially inner circumferential side of theconnecting body, which delimits the central opening, can act as an axialinsertion aid for the connector on the side of the filter head betweenthe corresponding starting sections of the coupling ribs and the edge ofthe coupling body.

The starting sections of the coupling ribs facing the filter head canadvantageously be arranged with axial offset in relation to thehead-side edge of the central opening.

In a further advantageous embodiment, the coupling device can compriseat least one circumferential, with respect to the coupling axis, outerseal.

The outer seal can advantageously be arranged on the connecting body.

The outer seal can advantageously be oriented radially outwardly withrespect to the coupling axis.

The outer seal can advantageously surround the at least one fluidopening and the central opening.

The outer seal can advantageously provide at least radial sealing withrespect to the coupling axis between the filter head and the spin-onfilter. It may separate a fluid-conducting area of the filter devicefrom the surroundings.

The easy-change filter, in particular the spin-on filter, of a filterdevice for fluid, in particular liquid, in particular oil or fuel, inparticular of an internal combustion engine, in particular of a motorvehicle, can advantageously comprise a filter-side coupling part of acoupling device that can be closed and released by way of a plug-inand/or rotational movement with respect to a coupling axis, thefilter-side coupling part being detachably couplable to a head-sidecoupling part of a filter head of the filter device.

On the easy-change filter, the coupling device can advantageouslycomprise at least one circumferential, with respect to the couplingaxis, inner seal, which can provide sealing between the filter head andthe easy-change filter at least axially with respect to the couplingaxis and can separate a dirty side of the easy-change filter from aclean side.

The object is further achieved by the filter device according to theinvention in that the same comprises a filter head, which includes ahead-side coupling part of a coupling device that can be closed andreleased by way of a plug-in and/or rotational movement with respect toa coupling axis, for an easy-change filter, in particular a spin-onfilter according to the invention, wherein the spin-on filter comprises:

-   -   a housing pot, in which a filter element is arranged;    -   a connecting body, which is arranged at the end face of the        housing pot and is provided with a central opening, and in        particular with at least one fluid opening that is radially        outwardly offset in relation to the central opening;    -   a filter-side coupling part of a coupling device for detachably        coupling the spin-on filter to a filter head of the filter        device, the coupling part being arranged on the central opening,        wherein the filter-side coupling part can be detachably coupled        to a connector of the head-side coupling part of the filter head        by way of a plug-in and/or rotational movement with respect to a        coupling axis, and wherein an inner seal is provided, having a        sealing surface which extends around the periphery of a centric        fluid channel and is axially offset in relation to the        filter-side coupling part toward the filter element, and against        which a circumferential sealing surface of a filter head-side        fluid connector can be sealingly placed so as to separate a        dirty side from a clean side of the spin-on filter.

Advantageously, the filter head can comprise at least one inflow and/orat least one outflow for the fluid.

The advantages and features described above in connection with thespin-on filter according to the invention and the advantageousembodiments thereof apply in corresponding fashion to the filter deviceaccording to the invention and the advantageous embodiments thereof, andvice versa.

The coupling device can advantageously comprise at least onecircumferential, with respect to the coupling axis, inner seal, whichcan provide sealing between the filter head and the easy-change filterat least axially with respect to the coupling axis and can separate adirty side of the easy-change filter from a clean side.

The filter device is suitable for filtering fluid. In particularliquids, in particular oil or fuel, can be filtered therewith.

The filter device can be used in internal combustion engines of motorvehicles. It can also be used in different internal combustion engines,in particular industrial motors. The invention can also be used outsideof internal combustion engines, in particular in motor vehicletechnology.

The filter device comprises a filter head, on which the easy-changefilter, and more particularly the spin-on filter, can be mounted. Thefilter head can advantageously have at least one inflow and/or at leastone outflow for the fluid. The filter head can preferably be rigidlyfixed to a frame. The frame can in particular be part of the internalcombustion engine and/or of the motor vehicle.

The filter head comprises a head-side coupling part of a coupling devicefor the easy-change filter. The filter head can advantageously comprisea first coupling part.

The easy-change filter comprises a filter-side coupling part of thecoupling device. The easy-change filter can advantageously comprise asecond coupling part.

The second coupling part can be detachably coupled to the first couplingpart. The coupling device can advantageously be closable and releasableby way of a combined plug-in movement and rotational movement (plug-inand/or rotational movement) with respect to a coupling axis. Combinedplug-in/rotational joints are easy and quick to close and open.Moreover, they are robust to tensile loads. In this way, a quick-releasefastener can be easily implemented with the coupling device according tothe invention, which is easy and quick to close and open.

In an advantageous embodiment, the inner seal can be an annular seal.

In a further advantageous embodiment, the inner seal can have arectangular profile. In this way, it can be seated against respectivecorresponding sealing surfaces of the filter head and of the easy-changefilter on axially opposing sides in a planar manner. The sealing actioncan thus be improved. Moreover, friction between the inner seal and thecorresponding sealing surfaces can thus be increased. The inner seal maythus additionally act as a screw-on protector. After compression of theinner seal, a rotation of the easy-change filter relative to the filterhead against the closing rotational direction may be made more difficultas a result of friction. In this way, the likelihood of the couplingdevice opening in an uncontrolled manner can be reduced.

Alternatively, the annular seal can also have a round or a differentangular profile. An extension of the profile may be larger in the axialdirection than in the radial direction. Alternatively, the profile maybe flat.

The inner seal can advantageously contribute to axial bracing of thecoupling device. In this way, it is possible to damp vibrations betweenthe easy-change filter and the filter head. Any potential noisedevelopment, in particular rattling, may thus be reduced.

In a further advantageous embodiment, the inner seal can be arrangedcoaxially with respect to the coupling axis. The axial sealing actioncan be improved during closing of the coupling device by a correspondingcompression axial with respect to the coupling axis.

In a further advantageous embodiment, the inner seal can be coupled tothe easy-change filter. It may advantageously be secured to theeasy-change filter. It may advantageously be arranged in an appropriatesealing groove on the easy-change filter. In this way, it is easy tocaptively preassemble.

In a further advantageous embodiment, the inner seal can be arranged onan end body, and more particularly an end cap, of a filter element, andmore particularly of a round filter element, of the easy-change filter.

In a further advantageous embodiment, the inner seal can surround athrough-opening to an element interior of a filter element of theeasy-change filter. The inner seal can thus easily separate the elementinterior from an exterior surrounding the filter element on the outside.The element interior can be located on the clean side or the dirty sideof the filter element. Correspondingly, the dirty side or the clean sidecan be located on the outside of the filter element.

The through-opening can advantageously be coaxial with respect to thecoupling axis. It can advantageously be connected to a connectingchannel. The connecting channel can advantageously extend coaxially withrespect to the coupling axis at least in some sections. The connectingchannel may be part of the filter head and/or of the head-side couplingpart. The connecting channel can advantageously be connected to the atleast one inflow or the at least one outflow for the fluid. This dependson whether a flow through the filter element from radially outside toradially inside, or vice versa, is possible.

A sealing surface for the inner seal can advantageously be provided onthe filter head side. The sealing surface can advantageously be coaxialwith respect to the coupling axis. The inner seal can be seated againstthe sealing surface in a planner and/or circumferentially closed manner.The sealing surface can advantageously surround the connecting channel.

In a further advantageous embodiment, the inner seal can be coaxial withrespect to a center pipe of the easy-change filter. In this way, theinner seal can be supported against the center pipe in a stable mannerin the axial direction.

In a further advantageous embodiment, at least one first of the couplingparts can comprise at least two first ramp sections extending helicallywith respect to the coupling axis, and the second coupling part cancomprise at least two second ramp sections extending helically withrespect to the coupling axis, which can be guided against each other forclosing the coupling device.

The first coupling part can advantageously comprise at least two first,in particular head-side, ramp sections that extend helically withrespect to the coupling axis. The second coupling part can comprise atleast two second, in particular filter-side, ramp sections that extendhelically with respect to the coupling axis. By using the helical rampsections, an installation space-optimized coupling device can beimplemented. By each of the coupling parts having at least tworespective ramp sections, the ramp sections of the coupling parts cancircumferentially abut each other in multiple locations when thecoupling parts are plugged together by way of a plug-in movement in thedirection of the coupling axis. In this way, the coupling parts can beattached to each other uniformly, in particular without tilting. Duringa subsequent rotational movement about the coupling axis, the rampsections of the coupling parts can mutually guide each other. In thisway, a closing process can be carried out easily and precisely.

The first ramp sections can advantageously overlap at least over aportion of the circumference. Advantageously, they can delimit ahelically extending first, in particular head-side, ramp groove on sidesthat are axially opposite each other with respect to the coupling axis.The at least one first ramp groove can advantageously have a U-shapedprofile. In this way, it can serve as a guide for the second rampsections on three sides, these being a radially outer or inner side andtwo axial sides. One of the axial sides can advantageously serve as aretaining surface, in particular a head-side retaining surface.

So as to close the coupling device, at least one of the second rampsections can be guided at least partially in one of the first rampsections. With the aid of the cooperation between the ramp sections andthe ramp grooves, it is possible to achieve precise, exact and stableguidance in the axial, radial and circumferential directions duringclosing of the coupling device. The corresponding second ramp sectionscan also be retained in a stable manner within the first ramp grooves.It is thus possible to implement a connection that is highly resilientaxially with respect to the coupling axis, in particular when it comesto tensile forces.

Multiple helical threads may be implemented by way of the multitude oframp sections on each of the coupling parts. The coupling device canthus be closed using relatively small rotational movements.Advantageously, the coupling device can be closed by way of a rotationalmovement of no more than 360°.

The slopes of the helical ramp sections can be uniform, in particularconstant. They may also vary along the ramp sections.

The first ramp sections can be identical. However, it is also possibleto use differing first ramp sections. Correspondingly, the second rampsections may be identical or different. The ramp sections of arespective one of the coupling parts can start at the same axial heightwith respect to the coupling axis. However, they may also start atdiffering axial heights.

The coupling parts can each be made of a single material or a materialmix. The coupling parts can advantageously be made of plastic material,aluminum and/or sheet metal or comprise such a material. The twocoupling parts can be made of the same material or of differingmaterials.

The easy-change filter can advantageously have a round cross-section.The easy-change filter can advantageously be coaxial with respect to afilter axis. The filter axis can advantageously coincide with thecoupling axis. The easy-change filter can advantageously comprise afilter element. The filter element can advantageously comprise a filtermedium that is closed circumferentially. The filter medium canadvantageously be pleated in a star-shaped or zigzag manner. The filtermedium can advantageously be sealingly coupled to an end body, inparticular an end cap, on at least one end face. The filter element canadvantageously be coaxial with respect to the filter axis. The filterelement can advantageously comprise a supporting body. The supportingbody can advantageously be a center pipe. The center pipe canadvantageously be located in an element interior of the filter element.The center pipe may extend between the end bodies.

Advantageously, the filter-side, in particular second, coupling part maybe a carrying and/or supporting part of the easy-change filter, inparticular of a housing of the easy-change filter.

Advantageously, the filter-side, in particular second, coupling part canbe designed with a cover part, in particular a connecting body, forclosing the housing of the easy-change filter. The filter-side couplingpart can advantageously be integrally joined to the cover part. In thisway, a complexity in terms of components can be reduced. The cover partcan advantageously include at least one passage, in particular an inletand/or an outlet, for the fluid into the easy-change filter or out ofthe same. The cover part can advantageously be fixed to a furtherhousing part, in particular a filter bowl, of the easy-change filter byway of a fixation element. The fixation element can advantageouslycomprise a sheet metal ring, which may be coupled to the further housingpart. The sheet metal ring can advantageously be coupled to the furtherhousing part by way of a crimped joint.

The coupling device can advantageously comprise at least one stop. Theat least one stop can be used to prevent the coupling device from beingmoved beyond the closed position thereof during the plug-in and/orrotational movement. In this way, the closed position can be preciselydefined. At least one of the stops can be located at the end of one ofthe ramp grooves. In this way, the corresponding facing end of the rampsection guided in the corresponding ramp groove can abut the stop andthus prevent further rotation.

Advantageously, each of the two coupling parts can have at least tworamp sections that extend helically with respect to the coupling axis.The ramp sections of the same coupling part can overlap over at leastpart of the circumference with respect to the coupling axis. The rampsections of the same coupling part can each delimit a helicallyextending ramp groove on sides that are axially opposite each other withrespect to the coupling axis. So as to close the coupling device, eachof the coupling parts can guide at least one of the ramp sections atleast partially in one of the ramp grooves of the respective othercoupling part.

The coupling device can advantageously be located between a dirty sideand a clean side of a filter element of the easy-change filter. Thecoupling device can thus advantageously be arranged within an outerseal, which can then seal the fluid-conducting area of the filter devicewith respect to the surroundings. A retaining function/coupling functionof the coupling device, and a sealing function between thefluid-conducting area of the filter device and the surroundings, canthus be separated from each other. In this way, the retainingfunction/coupling function and the sealing function can each beoptimized, in particular independently of one another.

Advantageously, at least one of the first ramp sections can comprise,outside the corresponding first ramp groove, an insertion ramp surfacewhich can transition into the corresponding first ramp groove. Theinsertion ramp surface can serve as an insertion aid so as to achieveexact insertion of the respective second ramp sections into thecorresponding ramp grooves.

Advantageously, the at least one first ramp section, together with theinsertion ramp surface, may be located on the filter head side. The atleast one second ramp section on the easy-change filter side, inparticular the spin-on filter side, can advantageously comprise, on aside located axially opposite the retaining surface, a feed ramp for thecorresponding insertion ramp surface of the at least one first rampsection.

At least one of the insertion ramp surfaces can advantageously extendhelically with respect to the coupling axis. In this way, guidance ofthe corresponding second ramp sections during the plug-in and/orrotational movement for closing/opening the coupling device can beimproved.

Advantageously, the at least one insertion ramp surface can transitionsteplessly into the corresponding ramp groove. In this way, uniformguidance can be achieved.

Advantageously, the at least one insertion ramp surface can be arrangedon the side of the at least one first ramp section which axially facesthe second coupling part.

Advantageously, at least two of the first ramp sections can becircumferentially offset in relation to each other at least in somesections In this way, each of the second ramp sections can be placedagainst a corresponding insertion ramp surface when the coupling partsare plugged into each other in any rotational orientation of theeasy-change filter with respect to the filter head. Guidance of the rampsections can thus be achieved in any rotational position of theeasy-change filter relative to the filter head.

Advantageously, at least one of the first ramp sections may extend overonly a portion of the circumference with respect to the coupling axis.In this way, the coupling device can be opened or closed by way of arotation of the easy-change filter of no more than 360° relative to thefilter head. The coupling device can be opened and closed quickly inthis way.

Advantageously, at least the first ramp sections can each extend acrossthe same angle of circumference. The coupling device can thus besymmetrical with respect to the coupling axis. In this way, theeasy-change filter can be mounted to the filter head in multiplerotational orientations. During closing of the coupling device, it iseasier to find a starting position from which controlled closure of thecoupling device is possible. The attachment of the easy-change filtercan thus be simplified.

Advantageously, an angle of circumference, across which each of the rampgrooves extends circumferentially, can correspond approximately to anangle of 360° divided by the number of first ramp sections. This canimprove the symmetry of the coupling device. Mounting of the easy-changefilter can be further simplified. Moreover, the circumferentialextension of the ramp grooves in relation to the overall size of thecoupling device can thus be optimized. It is thus possible to simplifythe coupling device as a whole. Moreover, the guidance and retention ofthe corresponding second ramp sections during assembly of the couplingdevice can be improved.

Advantageously, three first, in particular head-side, ramp sections maybe provided in each case. Advantageously, three second, in particularfilter-side, ramp sections may be provided in each case. Three rampsections allow the second coupling part to be easily and preciselyapplied, guided and retained.

The second ramp sections can advantageously each extend across the sameangle of circumference as the ramp grooves. In this way, each of thesecond ramp sections can be lowered completely into the correspondingramp grooves. The ramp grooves can implement a force transmission acrossthe entire circumferential extension thereof, together with the secondramp sections. The mechanical load-bearing capacity of the couplingdevice can thus be improved.

If three first ramp sections are used, the corresponding ramp groovescan advantageously each extend across an angle of circumference ofapproximately between 100° and 140°, and preferably 120°. The rampgrooves can thus overall encompass the entire circumference. In thisway, the coupling parts can be coupled along the entire circumference.

Advantageously, an angle of circumference, across which each of theinsertion ramp surfaces extends, can correspond approximately to anangle of 360° divided by the number of first ramp sections.Advantageously, the second ramp sections can each extend across the sameangle of circumference as the insertion ramp surfaces of the first rampsections. The second ramp sections can thus each be uniformly andprecisely placed against the corresponding insertion ramp surfaces andguided there.

If three first ramp sections are used, the three second ramp sectionscan advantageously each extend across an angle of circumference ofapproximately between 100° and 140°, and preferably 120°.

Advantageously, the first ramp sections can circumferentially delimithalf of each insertion ramp surface and half of each ramp groove. Inthis way, the second ramp sections can be uniformly seated against andbe guided on the insertion ramp surfaces. Moreover, the second rampsections can be held half in the ramp grooves approximately across theentire circumferential extension of the same. In this way, a stable, andmore particularly a tensile-resistant, coupling can be achieved.

A very large supporting surface can be implemented in a coupling devicehaving three respective ramp sections on the head side and on the filterside. In this way, high mechanical loads, and more particularly tensileloads, can be compensated for.

The ramp grooves can advantageously adjoin each other circumferentiallywith respect to the coupling axis. The ramp grooves can thus beconsecutively arranged with respect to the rotational movement forclosing/opening the coupling device. The ramp grooves may be arrangedwithout circumferential overlap. The ramp grooves can thus extend on thecircumferential sides of the first coupling part in a space-savingmanner.

Advantageously, the insertion ramp surfaces may optionally adjoin eachother circumferentially with respect to the coupling axis. The insertionramp surfaces can be arranged without circumferential overlap.

In a further advantageous embodiment, the coupling device can compriseat least one locking device having at least one head-side locking partand at least one filter-side locking part, which in the closed positionof the coupling device can form an unlockable connection with eachother. In this way, the closed coupling device can be mechanicallysecured at least when it is closed. The coupling device can thus beprevented from opening in an uncontrolled manner. The unlockableconnection can advantageously be closed and/or opened without the use ofa separate tool.

The unlockable connection can advantageously be a detent connection. Adetent connection is easy to close and open. The detent connection canadvantageously implement a mechanical resistance, which must be overcometo open the unlockable connection. The unlockable connection can thus beprevented from opening in an uncontrolled manner.

The unlockable connection, in particular the detent connection, canadvantageously generate a signal, in particular a signal that can bedetected acoustically and/or in a tactile manner, during locking. Inthis way, the closed state of the coupling device is easy to detect.

At least one of the locking parts, and more particularly at least one ofthe filter-side locking parts, can advantageously comprise a spring arm.The spring arm can advantageously be bent radially outwardly and/orradially inwardly in a spring-loaded manner with respect to the couplingaxis. A catch lug or a detent seat can advantageously be provided at onefree end of the spring arm. The at least one corresponding other lockingpart, and more particularly at least one of the head-side locking parts,can advantageously correspondingly comprise a detent seat or a catchlug. The detent seat or the catch lug of the spring arm canadvantageously latchingly engage with the catch lug or detent seat ofthe other locking part in the locked position of the unlockableconnection.

The at least one other locking part can advantageously have a guidesurface. The guide surface can ascend in a ramp-like manner in the axialdirection. The detent seat or catch lug may optionally be located at theend of the guide surface. During the rotational movement for closing thecoupling device, the spring arm of the one locking part, in particularoptionally the catch lug, can be guided on the guide surface of theother locking part.

The at least one spring arm can advantageously be arranged on theeasy-change filter side. In this way, the spring arm can be replacedjointly with the easy-change filter. This allows fatigue on the movablespring arm to be prevented, which may occur as a result of multipleinstances of opening and closing of the coupling device. The otherlocking part can advantageously be arranged on the filter head side.

The spring arm of the one coupling part can advantageously extendagainst a closing rotational direction of the easy-change filterrelative to the filter head.

The spring arm can advantageously be preloaded, the preload beingdirected radially inwardly with respect to the coupling axis. The otherlocking part can advantageously be arranged on a circumferential side ofthe corresponding coupling part which is located radially outside withrespect to the coupling axis.

The unlockable connection can advantageously be located outside aninterior of the easy-change filter. Advantageously, it can be located onthe outside of a cover body, in particular of a filter cover, of theeasy-change filter. It may be visible from the outside when theeasy-change filter is separated from the filter head. It is thuspossible to identify before mounting the easy-change filter whether theat least one filter-side locking part, and more particularly the springarm, is functional, in particular undamaged. The at least onefilter-side locking part, and more particularly the at least one springarm, can advantageously project beyond the cover body in the axialdirection. The filter-side locking part can advantageously be located ina circumferential extension of ribs extending circumferentially. Thefilter-side locking part can thus be protected.

Advantageously, the at least one filter-side locking part can comprisean in particular elastically movable, in particular deformable, lug, inparticular a catch lug.

The at least one filter-side locking part can advantageously be designedas a radially elastically deformable lug.

Advantageously, the at least one filter-side locking part can bearranged on the connecting body, in particular on the side facing thefilter head.

The at least one filter-side locking part can advantageously be arrangedon the side of the connecting plate facing the filter head.

Advantageously, multiple filter-side locking parts may be distributed,in particular uniformly distributed, circumferentially with respect tothe coupling axis.

In a further advantageous embodiment, the coupling device can compriseat least one circumferential, with respect to the coupling axis, outerseal which can provide sealing between the filter head and theeasy-change filter at least radially with respect to the coupling axisand can separate a fluid-conducting area of the filter device from thesurroundings. The outer seal can be used to separate thefluid-conducting areas, and more particularly areas between theeasy-change filter and the filter head, from the surroundings in asealed manner. The outer seal can be located on the dirty side or theclean side of the filter element of the easy-change filter. This dependson the flow direction of the fluid through the easy-change filter.

The outer seal can provide sealing in the radial direction with respectto the coupling axis. In this way, any potential compression of theouter seal can be substantially independent of a degree with which thecoupling device is closed. Mechanical loading of the outer seal can thusbe decreased.

The outer seal can advantageously be an O-ring seal. Alternatively, anangular, in particular flat, seal may be used. An O-ring seal has theadvantage that it is able to roll more easily off the correspondingradially inner and/or radially outer sealing surfaces during a plug-inmovement in the direction of the coupling axis. The radial sealingaction can be better defined and/or set with the O-ring seal than with aflat seal.

The outer seal can advantageously be secured on the easy-change filterside. It can advantageously be seated against the radial inside of acorresponding surface of the easy-change filter. Alternatively, it mayalso be seated against the radial outside of a corresponding surface ofthe easy-change filter.

A corresponding sealing surface, with which the outer seal can sealinglycooperate, can advantageously be arranged on the filter head side. Thesealing surface can be located radially outside or inside the outerseal. The sealing surface can advantageously be arranged on acorresponding outer sealing section on the filter head side. The outersealing section can advantageously be cylindrical. The outer sealingsection can advantageously be coaxial with respect to the coupling axis.A diameter of the sealing surface on the side facing the outer seal canwiden in the axial direction toward the end face from which the outerseal is moved toward the sealing surface during coupling of the couplingdevice. In this way, an insertion of the outer seal into the sealingsurface or an attachment of the outer seal onto the sealing surface canbe simplified. Moreover, the outer seal can be continuously, inparticular uniformly, compressed during the closing process of thecoupling device.

The outer seal can advantageously be arranged in a seal seat. The sealseat can advantageously be located on the easy-change filter side. Theseal seat can advantageously be a sealing groove. The sealing groove canadvantageously be open to the radial outside or to the radial inside.The sealing groove can advantageously be arranged on a cover element ofthe easy-change filter. The cover element can advantageously be annular.Advantageously, the cover element can be a sheet metal ring. The sealinggroove can advantageously be implemented by crimping of the sheet metalring. The cover element can advantageously be coupled to a housingelement, in particular a housing pot, of the easy-change filter, inparticular by way of a crimp.

On the side facing the open side of the sealing groove, the coverelement can comprise a seat, in particular an annular groove, for theouter sealing section of the filter head.

The outer seal can additionally or alternatively also provide axialsealing.

Advantageously, a progression of the ramp sections can be adapted to anarrangement of a circumferential, with respect to the coupling axis,outer seal of the coupling device such that, during closing of thecoupling device by way of a plug-in and/or rotational movement, duringan early closing phase, in particular during which the second rampsections are located in a respective starting region of the rampgrooves, the outer seal is located axially outside one of two sealingsections, in particular of a cylindrical outer sealing section, betweenwhich the outer seal provides sealing in the radial direction in theclosed position of the coupling device, and during a later closingphase, during which the second ramp sections in particular engage in arespective end region of the ramp grooves, the outer seal is compressedbetween the two sealing sections. In this way, the outer seal can berelieved during the closing phase when the ramp sections are locatedoutside or in the starting region of the ramp grooves. Loading, inparticular compression, of the outer seal does not take place until thelater closing phase when the ramp sections engage in the respective rampgrooves, and more particularly in the end regions of the same. In thisway, a circumferential movement, in particular chafing, of the outerseal between the sealing sections, in particular between the head-sideouter sealing section and the filter-side sealing groove, can beminimized. Mechanical loading of the outer seal, in particular wear, canthus be decreased. The slopes and/or the corresponding circumferentialextensions of the ramp grooves and/or optionally of the insertion rampsurfaces can advantageously be adapted to the arrangement, in particularthe position, of the outer seal.

The earlier closing phase can advantageously take place as the secondramp sections enter the ramp grooves. A first rotational angle duringthe rotation of the easy-change filter relative to the filter head,between the time at which the second ramp sections enter the rampgrooves and the early closing phase transitions to the late closingphase, can advantageously correspond approximately to a secondrotational angle between the time at which the earlier closing phasetransitions to the later closing phase and the later closing phase iscompleted.

If three ramp sections are used, the compression of the outer seal canadvantageously begin following the time at which the second rampsections enter the ramp grooves, subsequent to a rotation of theeasy-change filter by approximately 60°. After the easy-change filter isrotated another 60°, the outer seal can be completely compressed.

The object is moreover achieved by the filter head according to theinvention in that the filter head includes a head-side coupling part ofa coupling device that can be closed and released by way of a plug-inand/or rotational movement with respect to a coupling axis, for aneasy-change filter, in particular a spin-on filter according to theinvention, wherein a filter-side coupling part of the coupling device onthe easy-change filter can be detachably coupled to a connector of thehead-side coupling part of the filter head by way of a plug-in and/orrotational movement with respect to the coupling axis, and wherein ahead-side fluid connector includes a circumferential sealing surfaceagainst which an inner seal, which extends around the periphery of acentric fluid channel of the easy-change filter and is axially offset inrelation to the filter-side coupling part toward the filter element, canbe sealingly placed so as to separate a dirty side from a clean side ofthe spin-on filter.

The advantages and features described above in connection with thespin-on filter according to the invention and the filter deviceaccording to the invention and the advantageous embodiments of the sameapply in corresponding fashion to the filter head according to theinvention and the advantageous embodiments thereof, and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional advantages, features and details of the invention will beapparent from the description provided hereafter, which describes oneexemplary embodiment of the invention in more detail based on thedrawings. A person skilled in the art will expediently also individuallyconsider the features that are disclosed in combination in the drawings,the description and the claims and combine them to form meaningfulfurther combinations. In the schematic drawings:

FIG. 1 shows a longitudinal section of a filter system for engine oil ofan internal combustion engine of a motor vehicle, including a filterhead to which an easy-change filter is secured by way of a releasablecoupling device;

FIG. 2 shows a detailed view of another longitudinal section of thefilter system of FIG. 1 in the region of the coupling device;

FIG. 3 shows an isometric representation of the filter head of FIGS. 1and 2 without the easy-change filter, with a view onto the couplingside;

FIG. 4 shows a top view onto the coupling side of the filter head ofFIGS. 1 to 3 without the easy-change filter;

FIG. 5 shows an isometric representation of the easy-change filter ofFIGS. 1 and 2, with a view onto the coupling side; and

FIG. 6 shows a top view onto the coupling side of the easy-change filterof FIGS. 1, 2 and 5.

In the figures, identical components are denoted by the same referencenumerals.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 6 show a filter system 10 for engine oil of an internalcombustion engine of a motor vehicle in different perspectives, sectionsand detailed views.

The filter system 10 comprises a filter head 12, to which an easy-changefilter 14 is detachably secured. The filter head 12 is made of metal.The filter head 12 is rigidly coupled to the internal combustion engineand serves as a connecting part for the easy-change filter 14. Thefilter head 12 comprises an inlet 16 and an outlet 18 for the engineoil. The inlet 16 and the outlet 18 are connected to corresponding oillines of the internal combustion engine in a manner that is not offurther interest here.

The filter head 12 moreover comprises a head-side coupling part 20 of areleasable coupling device for coupling the easy-change filter 14 to thefilter head 12, the coupling device being denoted in the overall byreference numeral 22. The head-side coupling part 20 is made of metal.The head-side coupling part 20 has a diameter greater than that of aninner diameter of the filter element 70. The side of the head-sidecoupling part 20 facing the easy-change filter 14 has the shape andfunction of a connector. The head-side coupling part 20 is screwed intoa hollow connecting cylinder 24, which is integrally joined to thefilter head 12. The connecting cylinder 24 includes an internal thread.The connecting cylinder 24 is coaxial with respect to a filter axis 26.Instead of being screwed as a separate component to the filter head 12,the head-side coupling part 20 can also be integrally joined thereto.

When referring hereafter to “axial,” “radial,” “coaxial” or“circumferential,” this description relates to the filter axis 26,unless indicated otherwise.

The head-side coupling part 20 comprises a cylindrical connecting sleevesection 28 having an external thread matching the internal thread of theconnecting cylinder 24. When the easy-change filter 14 is attached, theconnecting sleeve section 28 is likewise coaxial with respect to thefilter axis 26.

An interior of the connecting sleeve section 28 is connected to theoutlet 18 of the filter head 12. The connecting sleeve section 28 has asingle step on the radially inner circumferential side thereof. Theinside cross-section of the connecting sleeve section 28 isapproximately hexagonal on the expanded side facing the easy-changefilter 14, wherein the corners are slightly rounded. The insidecross-section of an imaginary incircle on the side of the outlet 18 issmaller than the inside cross-section of the connecting sleeve section28 on the side facing the easy-change filter 14.

The connecting cylinder 24 is surrounded on the radial outside by aninlet ring chamber 30 of the filter head 12.

An end face of the connecting sleeve section 28 facing the easy-changefilter 14 forms an annular coaxial sealing surface 32.

The connecting sleeve section 28 of the head-side coupling part 20 issurrounded on the radial outside by an outer cylinder section 34. Thecircumferential wall of the outer cylinder section 34 has approximatelythe shape of a hollow circular cylinder. The outer cylinder section 34is coaxial with respect to the filter axis 26. It extends in the axialdirection approximately from the axial center plane of the connectingsleeve section 28 in the direction toward the end face of the connectingsleeve section 28 which faces the easy-change filter 14. On the sidefacing the filter head 12, the outer cylinder section 34 is integrallyjoined to the radially outer circumferential side of the connectingsleeve section 28 by way of a radial ring disk section 36.

A plurality of radial connecting walls 40 are arranged in an annularchamber 38 between the radially inner circumferential side of the outercylinder section 34 and the radially outer circumferential side of theconnecting sleeve section 28. The radial connecting walls 40 are eachintegrally joined on the radial outside to the outer cylinder section34, and on the radial inside to the connecting sleeve section 28 and toa bottom side of the radial ring disk section 36. The radial connectingwalls 40 each extend radially and axially. They are arranged in anapproximately star-shaped manner seen in the direction of the filteraxis 26.

A total of three head-side ramp sections 42 are arranged on the radiallyouter circumferential side of the outer cylinder section 34. Thehead-side ramp sections 42 are identical in terms of the expanses andshapes thereof. The head-side ramp sections 42 each extend helicallywith respect to the filter axis 26. A slope direction of the head-sideramp sections 42 corresponds to a known right-handed thread.

A closing rotational direction 43 of the easy-change filter 14 relativeto the filter head 12, which is indicated by an arrow in FIGS. 1, 2, 4and 6, for closing the coupling device 22 corresponds to that of a knownright-handed thread. The closing rotational direction 43 extendsclockwise from the easy-change filter 14 toward the filter head 12 seenin the axial direction.

The head-side ramp sections 42 each extend approximately across an angleof circumference of 240°. The head-side ramp sections 42 are arrangedoffset in relation to each other. Two of the head-side ramp sections 42in each case overlap across half of the circumferential extensionsthereof. The starting sections of the head-side ramp sections 42 areeach located on the free end face of the outer cylinder section 34 whichfaces the easy-change filter 14. The ends of the head-side ramp sections42 are each circumferentially located where the next but one head-sideramp section 42 begins, seen against the closing rotational direction43.

Each head-side ramp section 42 is composed of two regions seencircumferentially. A first region including a respective insertion rampsurface 44 extends circumferentially from the starting section of arespective head-side ramp section 42 to the starting section of therespective next head-side ramp section 42, seen against the closingrotational direction 43. The insertion ramp surfaces 44 are freelyaccessible in the axial direction, seen from the easy-change filter 14.They each extend in the radial direction and helically in thecircumferential direction. The insertion ramp surfaces 44 each extend inthe radial direction across the entire radial wall thickness of theouter cylinder section 34.

A respective region including a groove ramp surface 46 adjoins therespective insertion ramp surface 44. The circumferential extension ofthe insertion ramp surface 44 corresponds to the circumferentialextension of the groove ramp surfaces 46. They each extend across anangle of circumference of 120°. The groove ramp surfaces 46 are locatedon the radial outside of the outer cylinder section 34. The regionsincluding the groove ramp surfaces 46 each overlap the subsequenthead-side ramp sections 42, seen against the closing rotationaldirection 43. The groove ramp surface 46 of the front head-side rampsection 42, seen in the closing rotational direction 43, in each caseoverlaps the insertion ramp surface 44 of the subsequent head-side rampsection 42. The groove ramp surfaces 46 extend in the radial directionapproximately across half the radial wall thickness of the outercylinder section 34. The insertion ramp surfaces 44 transition withoutsteps into the groove ramp surfaces 46. The groove ramp surfaces 46 havethe same slope as the insertion ramp surfaces 44. Each of the grooveramp surfaces 46 starts, in the circumferential direction, at the levelof the starting section of the respective subsequent clockwise head-sideramp section 42. The groove ramp surfaces 46 end at the level of thestarting section of the respective circumferentially next but onehead-side ramp section 42.

The groove ramp surfaces 46 delimit a respective ramp groove 48 on anaxial side. On the axially opposing side, the ramp grooves 48 are eachdelimited by a head-side retaining surface 49 of the correspondingregion of the subsequent head-side ramp section 42, the retainingsurface being located axially opposite the insertion ramp surface 42.The ramp grooves 48 have a constant axial extension in thecircumferential direction. Seen in the circumferential direction, theradial extension of the same is likewise constant.

Three detent elements 50 of a locking device of the coupling device 22are arranged on the radially outer circumferential side of the outercylinder section 34, the locking device being denoted in the overall byreference numeral 52. Each of the detent elements 50 is integrallyjoined to the outer cylinder section 34. The detent elements 50 areradial elevations. The detent elements 50 are arranged in the axialdirection approximately at the level of the radial ring disk section 36.

Each of the detent elements 50 is approximately wedge-shaped. In a rearregion with respect to the closing rotational direction 43 of thecoupling device 22, each detent element 50 has a sloping guide surface54. The guide surface 54 is provided at the radially outercircumferential side of the detent elements 50. A respective detentrecess 56 adjoins the end of the guide surface 54. The radial expansionof the detent elements 50 is smaller in the region of the detent recess54 than in the region of the end of the guide surface 54 which iselevated in the radial direction. Each detent element 50 extendscircumferentially across an angle of circumference of approximately 25°to 30°. The transition from the guide surface 54 to the correspondingdetent recess 56, seen circumferentially, is located approximately atone level with the end of one of the head-side ramp sections 42 and thestart of the next but one head-side ramp section 42, seen against theclosing rotational direction 43.

The connecting cylinder 24 and the head-side coupling part 20 aresurrounded by a coaxial circular cylindrical outer sealing section 58.The free end face of the outer sealing section 58 faces the easy-changefilter 14. The inside cross-section of this section increases toward thefree end face thereof. The radially inner circumferential side of theouter sealing section 58 forms an outer sealing surface 60.

Furthermore, the filter bowl 12 comprises an outer collar 62, whichextends in sections coaxially with respect to the filter axis 26 andsurrounds the radial outside of the outer sealing section 58 over aportion of the circumference.

The easy-change filter 14 is designed as a spin-on filter having a roundcross-section. It is substantially coaxial with respect to the filteraxis 26. The easy-change filter 14 comprises a filter bowl 64, in theopen side of which a filter cover 66 is secured. The filter bowl 64 hasan outwardly curved filter bottom 68.

A coaxial filter element 70 is arranged in the filter bowl 64. Thefilter element 70 comprises a circumferentially closed filter medium 72that is pleated in a zigzag manner. At the respective end faces, thefilter medium 72 is sealingly connected to a connecting end cap 74, atthe top, see FIG. 1, and a counter end cap 76, at the bottom.

The connecting end cap 74 is shown in detail in FIGS. 2, 5 and 6. It islocated on the side of the filter element 70 facing the filter cover 66.The filter medium 72 surrounds an element interior 78 of the filterelement 70. The element interior 78 is located on a clean side of thefilter element 70.

The counter end cap 76 closes the element interior 78 on the end face ofthe filter element 70 facing the filter bottom 68. Multiple springelements 80 are supported on the outside of the counter end cap 76 whichfaces the filter bottom 78, and are supported on the other side on thespring bottom 68.

The filter element 70 is surrounded on the radial outside by adirty-side annular chamber 82, which is delimited by the radially innercircumferential side of the filter bowl 64.

A coaxial center pipe 84 extends in the element interior 78 between thecounter end cap 76 and the connecting end cap 74. A circumferential wallof the center pipe 84 is pervious to the engine oil. A radially innercircumferential side, which is to say radially inner pleated edges, ofthe filter medium 72 is supported on the radially outer circumferentialside of the center pipe 84.

The connecting end cap 74 comprises a coaxial outlet opening 86 for thefiltered engine oil. The outlet opening 86 forms a centric oil drainchannel. A coaxial seal seat cylinder 88 is integrally provided on theaxially outer side of the connecting end cap 74. A radially innercircumferential side of the seal seat cylinder 88 is stepped. On the endface facing away from the element interior 78, the seal seat cylinder 88comprises a coaxial sealing groove 90 including an annular inner seal92. The inner seal 92 is arranged offset axially with respect to thefilter axis 26 in relation to the filter-side coupling part 108 towardthe interior of the easy-change filter 14. The inner seal 92 is designedas a flat seal. The inner seal 92 has a sealing surface 93 extendingaround the outlet opening 86. When the easy-change filter 14 is mounted,the side of the inner seal 92 facing away from the element interior 78is sealingly seated against the sealing surface 32 of the connectingsleeve section 28 of the head-side coupling part 20. The inner seal 92acts in the axial direction. The inner seal 92 separates a dirty side ofthe filter element 70, radially outside the seal seat cylinder 88, in asealed manner from a clean side, radially inside the seal seat cylinder88. The smallest inside radius of the seal seat cylinder 88 correspondsapproximately to the inside radius of an imaginary incircle of theconnecting sleeve section 28 on the side having an expandedcross-section.

On the radial outside, the seal seat cylinder 88 is braced by way ofsupporting elements 94 against the radially extending section of theconnecting end cap 74. The supporting elements 94 each extend radiallyand axially. In addition, inner supporting elements 96 are provided onthe radially inner circumferential side of the seal seat section 88,bracing a ring section of the seal seat cylinder 88 that surrounds thesealing groove 90 on the radial inside.

The filter cover 66 has the shape of a ring having an approximatelyrectangular profile. The filter cover 66 is made of metal. The filtercover 66 has the function of a connecting plate for coupling theeasy-change filter 14 to the filter head 12. The filter cover 66includes a receiving opening 98 that is coaxial with respect to thefilter axis 26, for receiving the outer cylinder section 34 of thehead-side coupling part 20. Within the radially outer edge of the filtercover 66, a coaxial annular groove 100 is arranged on the outside facingaway from the filter bottom 68 for accommodating a cover sheet metalring 102. A plurality of inlet through-ports 104 are arranged radiallybetween the annular groove 100 and the receiving opening 98. The inletports 104 each extend in parallel to the filter axis 46. They connectthe inlet ring chamber 30 of the filter head 12 to the interior of thefilter bowl 64, or the dirty-side annular chamber 82.

Three filter-side ramp sections 106 are arranged on the radially innercircumferential side of the filter cover 66. The ramp sections 106implement respective coupling ribs. The filter-side ramp sections 106each extend radially inwardly from the radially inner circumferentialside of the filter cover 66. The extension and the circumferentialprogression of the filter-side ramp sections 106 are substantiallyidentical. The sides of the filter-side ramp sections 106 facing theinterior of the filter bowl 64 form respective filter-side retainingsurfaces 107. The sides of the filter-side ramp sections 106 facing awayfrom the interior of the filter bowl 64 form respective filter-side feedramps 109. The filter-side retaining surfaces 107 and the feed ramps 109run approximately parallel to each other. The filter-side ramp sections106 each extend helically with respect to the filter axis 26,analogously to the head-side ramp sections 42. The slopes of the samecorrespond to those of the head-side ramp sections 42. The filter-sideramp sections 106 each extend across an angle of circumference of 120°with respect to the filter axis 26. The filter-side ramp sections 106 donot overlap. The starting sections 111 of the filter-side ramp sections106 are located on the axial side facing away from the interior of thefilter bowl 64. The starting sections 111 face the filter head 12 whenthe easy-change filter 14 is mounted. The starting sections 111 arespaced from a head-side radially inner edge of the filter cover 66 whichfaces away from the element interior 78 and surrounds the outlet opening86. Seen circumferentially, the starting section 111 of each filter-sideramp section 106 is located at one level with the end of the precedingfilter-side ramp section 106 in the closing rotational direction 43. Theaxial heights of the filter-side ramp sections 106 are constant acrossthe circumference. They correspond to the axial heights of the rampgrooves 48 of the head-side ramp sections 42. The filter-side rampsections 106 and the receiving opening 98 together form a filter-sidecoupling part 108 of the coupling device 22. The sealing surface 93 ofthe inner seal 92 is offset axially in relation to the filter-sidecoupling part 108 toward the filter element 70. The sealing surface 93is also positioned radially inward from the filter-side coupling part108 and the head-side coupling part 20. A diameter of the head-sidecoupling part 20 is greater than an inner diameter of the filter element70.

Three detent spring elements 110 are arranged on the outside of thefilter cover 66 facing away from the interior of the filter bowl 64. Thedetent spring elements 110 are part of the locking device 52. Each ofthe detent spring elements 110 has a retaining section 112. Theretaining section 112 is integrally joined to the filter cover 66radially between the annular groove 100 and the receiving opening 98. Arespective spring arm section 114 of the detent spring elements 110 isintegrally joined to the retaining section 112. The spring arm sections114 are each located on the front side of the retaining sections 112,seen in the closing rotational direction 43. The spring arm sections 114each extend circumferentially across an angle of circumference ofapproximately 30°. The spring arm sections 114 can be bent outwardly ina spring-loaded manner on the retaining sections 112 in the radialdirection. At the respective free ends facing away from the retainingsections 112, each of the spring arm sections 114 transitions into acatch lug 116. The catch lugs 116 extend radially inwardly. Each of thecatch lugs 116 is located on the same circumferential side as a startingsection 111 of one of the filter-side detent sections 106 and an end ofthe respective preceding filter-side ramp section 106.

The cover sheet metal ring 102 has a profile that is bent multipletimes. The radially outer circumferential side of the ring is rigidlyconnected to a free edge of the filter bowl 64 by way of a crimped joint120. Radially inside the crimped joint 120, the cover sheet metal ring102 has an approximately rectangular, circumferentially closed firstbending section. In the region of the first bending section, the coversheet metal ring 102 comprises a collar 122, which engages in theannular groove 100 of the filter cover 66, on the side facing the filtercover 66.

On the outside of the cover sheet metal ring 102 facing away from thefilter cover 66, the collar 122 forms a receiving groove 124 for theouter sealing section 58 of the filter head 12.

The radially inner circumferential side of the cover sheet metal ring102 is bent to form a U-shaped profile, the opening of which pointsradially outwardly. The U-shaped profile includes a coaxial,circumferentially closed sealing groove 126. An outer seal 128 isarranged in the sealing groove 126. The outer seal 128 is an O-ringseal. The outer seal 128 is oriented radially outwardly with respect tothe filter axis 26. The outer seal 128 acts in the radial direction.

On the inside edge facing axially away from the filter cover 66, thecover sheet metal ring 102 comprises a plurality of notches 130distributed over the circumference.

When the easy-change filter 14 is mounted, the outer seal 128 issealingly seated against the outer sealing surface 60 of the outersealing section 58. The outer seal 128 separates the dirty side of thefilter element 70, or the inlet ring chamber 30, from the surroundings132.

For coupling to the filter head 12, the easy-change filter 14 isinitially moved, with the filter cover 66 first, axially with respect toa coupling axis, which in the exemplary embodiment coincides with thefilter axis 26, toward the head-side coupling part 20 of the filter head12 in a plug-in movement. The outer cylinder section 34 is plugged intothe receiving opening 98 of the filter cover 66 until the filter-sideramp sections 106 axially abut the insertion ramp surfaces 44 of thehead-side ramp sections 42. The outer sealing section 58 is locatedaxially remote from the outer seal 128.

Using a rotational movement of the easy-change filter 14 in the closingrotational direction 43, the filter-side coupling part 108 is screwedinto the head-side coupling part 20. In this process, the respectivefilter-side ramp sections 106 engage in one of the ramp grooves 48.Following a rotational angle of 60° from the time at which thefilter-side ramp sections 106 begin to be lowered into the ramp grooves48, the outer seal 128 begins to be seated against the outer sealingsurface 60 of the outer sealing section 58 and is guided in the inletregion having an expanded cross-section when the easy-change filter 14is rotated further.

Following further rotation by 60°, the front ends, in the closingrotational direction 43, of the filter-side ramp sections 160 abut therear ends of the ramp grooves 48. The ends of the ramp grooves 48 formstops, which prevent the easy-change filter 14 from being rotatedfurther when the coupling device 22 is closed.

When the coupling device 22 is closed, the inner seal 92 is sealinglyseated against the sealing surface 32 of the connecting sleeve section28 in a radially compressed manner.

In an end phase of the closing movement, the catch lugs 116 of thespring arm sections 114 of the detent spring elements 110 furthermoreabut the respective rear ends, in the closing rotational direction 43,of the guide surfaces 54 of the detent elements 50. When the easy-changefilter 14 is rotated further in the closing rotational direction 43, thecatch lugs 116 are guided on the guide surfaces 54. When the couplingdevice 22 is closed, the catch lugs 116 latchingly engage the respectivedetent recesses 56 of the detent elements 50. The latching engagement ofthe catch lugs 116 generates an audible sound.

The latchingly engaged catch lugs 116 make it more difficult to open thecoupling device 22 by rotating the easy-change cylinder 14 against theclosing rotational direction 43. Moreover, the compressed inner seal 92makes it more difficult to open the coupling device 92 as a result offriction.

The easy-change filter 14 is removed from the filter head 12 by rotatingthe easy-change filter 14 against the closing rotational direction 43.For this purpose, initially the spring force of the spring sections 114and the frictional force between the inner seal 92 and the sealingsurface 32 must be overcome.

During operation of the filter system 10, the engine oil to be filteredis fed through the inlet 16 of the filter head 12 to the inlet ringchamber 30. From there, the engine oil reaches the dirty-side annularchamber 82 of the easy-change filter 14 through the inlet ports 104. Theengine oil to be filtered flows through the filter medium 72 from theradial outside to the radial inside and is purified. The purified engineoil leaves the element interior 78 through the outlet opening 86 andreaches the interior of the connecting sleeve section 28, which servesas a fluid connector having an oil duct. The interior of the connectingsleeve section 28 thus fluidically communicates with the outlet opening86. From there, the purified engine oil flows into the outlet 18 of thefilter head 12 and leaves the filter system 10.

In an alternative design of the filter device, it is possible to provideinlet ports on the filter head 20, and specifically on the ring disksection 36 of the connecting sleeve section 28, so that the untreatedfluid can flow through head-side inlet ports into the filter, as analternative or in addition to the inlet via the inlet ports 104.

What is claimed is:
 1. A spin-on filter (14) for a filter device (10)for fluid, the spin-on filter (14) comprising: a housing pot (64), inwhich a filter element (70) is arranged; a connecting body (66), whichis arranged at an end face of the housing pot (64) and is provided witha central opening (98), and at least one fluid opening (104) that isradially outwardly offset in relation to the central opening; afilter-side coupling part (108) of a coupling device (22) for detachablycoupling the spin-on filter (14) to a filter head (12) of the filterdevice (10), the coupling part being arranged on the central opening(98); wherein the filter-side coupling part (108) is detachably coupledto a connector of a head-side coupling part (20) of the filter head (12)by way of a plug-in and/or rotational movement with respect to acoupling axis (26); and wherein an inner seal (92) is provided, having asealing surface (93) which extends around the periphery of a centricfluid channel (86) and is axially offset in relation to the filter-sidecoupling part (108) toward the filter element (70), and against which acircumferential sealing surface (32) of a filter head-side fluidconnector (28) is sealingly placed so as to separate a dirty side (82)from a clean side (78) of the spin-on filter (14); and wherein saidsealing surface (93) is positioned radially inward from said filter sidecoupling part (108) and said head side coupling part (20); wherein thefilter-side coupling part (108) includes a plurality of coupling ribs(106), which are distributed in the circumferential direction of thecoupling axis (26) on the central opening (98) and wherein the sealingsurface 93 of the inner seal 92 abbutingly axially contacts the sealingsurface (32) of the head-side fluid connector by axial movement of thespin on filter 14, and wherein the coupling device (22) includes atleast one circumferential with respect to the coupling axis 26, outerseal (128) directed radially outward to which provides sealing betweenfilter head 12 and the spin-on filter (14) at least radially withrespect to the coupling axis (26) and separates a fluid conducting area(30) at the filter device (10) from a surrounding (132), and said innerseal surface (93) is along said axis (26) more closer to said filterelement (70) than said outer seal (128).
 2. The spin-on filter accordingto claim 1, wherein the inner seal (92) is coupled to the filter element(80).
 3. A filter device (10) for fluid, comprising a filter head (12),which includes a head-side coupling part (20) of a coupling device (22)that is closed and released by way of a plug-in and/or rotationalmovement with respect to a coupling axis (26), for a spin-on filter(14); the spin-on filter (14) including: a housing pot (64), in which afilter element (70) is arranged; a filter-side coupling part (108) of acoupling device (22) for detachably coupling the spin-on filter (14) toa filter head (12) of the filter device (10), the coupling part beingarranged on the central opening (98); wherein the filter-side couplingpart (108) includes a plurality of coupling ribs (106), which aredistributed in the circumferential direction of the coupling axis (26)on the central opening (98) wherein the filter-side coupling part (108)is detachably coupled to a connector of the head-side coupling part (20)of the filter head (12) by way of a plug-in and/or rotational movementwith respect to the coupling axis (26); and wherein an inner seal (92)is provided, having a sealing surface (93) which extends around theperiphery of a centric fluid channel (86) and is axially offset inrelation to the filter-side coupling part (108) toward the filterelement (70), and against which a circumferential sealing surface (32)of a filter head-side fluid connector (28) is sealingly placed so as toseparate a dirty side (82) from a clean side (78) of the spin-on filter(14); and wherein said inner seal (92) is positioned radially inwardfrom said filter side coupling part (92) and said head-side couplingpart (20); and wherein the sealing surface area of the inner sealabbutingly contacts the sealing surface (32) of the head-side fluidconnector by axial movement of the spin on filter (14), and wherein thecoupling device (22) includes at least one circumferential with respectto the coupling axis 26, outer seal (128) directed radially outward toprovide sealing between filter head 12 and the spin-on filter (14) atleast radially with respect to the coupling axis (26) and can separate afluid conducting area (30) at the filter device (10) from a surrounding(132), and said inner seal surface (93) is along said axis (26) moreadjacent to said filter element (70) than said outer seal (128).
 4. Thefilter device (10) according to claim 3, wherein the inner seal (92)seals between the filter head (12) and the spin-on filter (14) at leastaxially with respect to the coupling axis (26).
 5. The filter deviceaccording to claim 3, wherein the inner seal (92) is an annular seal. 6.The filter device according to claim 3, wherein the inner seal (92) hasa rectangular profile.
 7. The filter device according to claim 3,wherein the inner seal (92) is arranged coaxially with respect to thecoupling axis (26).
 8. The filter device according to claim 3, whereinthe inner seal (92) is coupled to the spin-on filter (14).
 9. The filterdevice according to claim 3, wherein the inner seal (92) is arranged onan end body which is an end cap (74) of a filter element of the spin-onfilter (14).
 10. The filter device according to claim 3, wherein theinner seal (92) surrounds a through-opening (86) to an element interior(78) of a filter element (70) of the spin-on filter (14).
 11. The filterdevice according to claim 3, wherein a head-side coupling part (20)includes at least two first ramp sections (42) extending helically withrespect to the coupling axis (26); and a filter-side coupling part (108)includes at least two second ramp sections (106) extending helicallywith respect to the coupling axis (26), which are guided against eachother for closing the coupling device (22).
 12. The filter deviceaccording to claim 3, wherein the coupling device (22) includes at leastone locking device (52) having at least one head-side locking part (50);and at least one filter-side locking part (110), which in the closedposition of the coupling device (42) forms an unlockable connection witheach other.
 13. The filter device of claim 1 wherein an inner diameterof said filter-side coupling part (108) is more radially closer to aninner diameter of said filter element (70) than an outer diameter ofsaid pot (64).
 14. The filter device of claim 1 wherein an outerdiameter of said head-side coupling part (20) is greater than an innerdiameter of said filter element (70).